The present invention relates generally to the field of communications, and more specifically to radio-frequency data communications.
Acquisition is an important and often difficult task for any modem. This is especially true for waveforms having higher data rates that employ complex modulations such as continuous-phase modulation (CPM). In ultra-high frequency (UHF) satellite communications (SATCOM) military waveform standards, several higher data rate waveforms are defined, for example MIL-STD-188-181B. The majority of these modes rely on CPM for both the waveform preamble and data. In all cases, the preamble uses a type of CPM called minimum-shift keying (MSK). The specification defines the MSK preamble, and further requires that the signal be acquired 95 percent of the time with 90 percent confidence at a bit-error rate of 10−3.